android 线程池中的完成回调

Question

我开发了一个应用程序来读取点类型的 KML 文件，然后使用 Google Elevation API 更新它们的高程。如您所见，它接收点的纬度和经度，并在其后附加 API 键以检索海拔。因为我的 KML 文件有多个点，所以我使用 ThreadPool 读取点的纬度和经度，用键附加它，然后将 URL 发送到 Google 高程 API.Something，如下所示：

ScheduledThreadPoolExecutor executor = (ScheduledThreadPoolExecutor) Executors.newScheduledThreadPool(CORE_NUMBERS + 1);
    String providerURL = provider.getServiceURL();
    String providerKey =  provider.getServiceAPIkey();

for (PointFeature p: points) {

        String coordinate = p.getLatitude() + "," + p.getLongitude();       // get latitude and longitude of the feature
        String url = providerURL + "locations=" + coordinate + providerKey; // creating the url of web service which contains coordinate
        HeightTask task = new HeightTask(url, p);                           // task of each points            
        executor.execute(task);       
      }

heightTask class 是我解析 API 的 JSON 结果并获取高度并设置 heithUpdate 标志的地方。这是片段：

public class HeightTask implements Runnable {

private String url;    
private Feature feature;

public HeightTask(String url, Feature f) {

    this.feature = f;
    this.url = url;    
}

@Override
public void run() {

    if (feature instanceof PointFeature) {

        float height = GoogleAPIJsonParser.parsePoint(HttpManager.getData(url));
        if (height != Float.NaN){

            feature.updateHeight(height);
            feature.setHeightUpdated(true);
            Log.d("elevationPoint",height+"");
        }
    } 
}
}

我需要的是一个回调，以了解图层中所有点的高程是否已更新。 threadPool 中是否有任何模式或只是遍历所有点并检查 hieghtUpdate 标志？

Answer 1

修改代码如下。

更改 HeightTask 以实现 Callable 接口。

准备一组可调用任务并使用invokeAll()

提交

 List<HeightTask > futureList = new ArrayList<HeightTask >();
 for (PointFeature p: points) {

    String coordinate = p.getLatitude() + "," + p.getLongitude();       // get latitude and longitude of the feature
    String url = providerURL + "locations=" + coordinate + providerKey; // creating the url of web service which contains coordinate
    HeightTask task = new HeightTask(url, p);    
    futureList.add(taks);     
 }
 executor.invokeAll(futureList);

全部调用：

<T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
                       throws InterruptedException

Executes the given tasks, returning a list of Futures holding their status and results when all complete. Future.isDone() is true for each element of the returned list. Note that a completed task could have terminated either normally or by throwing an exception.

android 线程池中的完成回调

Completion Callback in android thread pool

multithreading

android

callback

threadpool